Consequences and Correctives Related to Lake Acidification, Liming and Mercury in Fish – A Case-Study for Lake Huljesjön, Sweden, Using the LakeWeb-model

This work exemplifies how a given lake (Lake Huljesjön, Sweden) would likely respond to changes in pH-values and to liming (a standard measure against anthropogenic acidification). The basic questions are: How would a liming influence pH? How long would the changes last? How would the changes influence the structure and function of lake ecosystems? The work uses a comprehensive lake ecosystem model, LakeWeb, which accounts for production, biomasses, predation, abiotic/biotic interactions of nine key functional groups of organisms, phytoplankton, bacterioplankton, two types of zooplankton (herbivorous and predatory), two types of fish (prey and predatory), zoobenthos, macrophytes and benthic algae. LakeWeb is a dynamic model and gives weekly variations. It has been critically tested using empirical data and regressions from many lakes. Those tests are not presented here but have shown that the model can capture typical functional and structural patterns in lakes very well. This gives credibility to the results presented in this work, which would be very costly to obtain in the traditional manner by extensive field studies in one or a few lakes. This work presents for the first time predictions at the ecosystem level of how functional groups of organisms (and not individual species) are likely to respond to acidification and liming. Two existing dynamic models, one for liming, the other for Hg-concentrations in fish, have been added to the LakeWeb-model. These two models have previously been tested and proven to yield good predictions. The results presented here indicate that there are several probable changes in the structure and function of the lake foodweb related to acidification and liming. The predicted changes in macrophyte cover will influence the predation pressure on fish, and thereby the fish biomass. Reductions in primary production at low pH-values will cause reductions in fish biomass. There are several interesting compensatory effects between factors that increase fish biomass and factors that tend to decrease the biomass. Such matters can be handled quantitatively by the LakeWeb-model.     

Oxygen saturation trends in the Baltic Sea

Marine monitoring programmes are seldom planned and realized to fulfil the requirements of the statistical methods used. The shortcomings of these methods are rarely discussed in the literature. In this work two different methods for trend analysis are applied to a real case and attention is given to the possible violation of the underlying assumptions. Long-term changes in oxygen supersaturation in the Baltic Sea are the object of the study. Linear regression and non-parametric methods are those chosen. The linear regression gave significantly increasing trends of oxygen saturation in Arkona, Eastern Gotland basin and in the Bothnian Sea, but the tested assumptions turned out to be violated. The corresponding non-parametric trend test only confirmed the increasing trend in Arkona. It is suggested that non-parametric methods, like the one used in this work, should be favoured in the future for similar types of marine environmental data.     

A one year study of the seasonal variations of sDDT and PCB levels in fish from heated and unheated areas near a nuclear power plant

An investigation of the influence of excess heat discharge from a nuclear power plant on the residual levels of the sDOT and PCB in roach and perch has been made during a period of one year. A seasonal variation of the residual concentrations was observed, with the highest levels during spring and early summer and lower more stable levels in the autumn. Significantly higher levels of the sDDT and PCB was observed in perch from the cooling water recipient as compared to values in perch from the intake area. No significant differences could however be verified for roach. The result stress the importance that, in a monitoring program, a sampling period with stable ecological conditions is selected.     

Partition coefficients of organic chemicals derived from reversed phase thin layer chromatography: Evaluation of methods and application on phosphate esters,polychlorinated paraffins and some PCB-substitutes

The application of reversed phase high performance thin layer chromatography has been evaluated for determination of octanol-water partition coefficients (P_oct) of organic chemicals. Best correlations between log P_oct and R_M-values were obtained on a C₁₈-bonded stationary phase using acetone-water or acetonitrile-water mixtures as eluting solvent. The latter mixture is preferred in work with high pressure liquid chromatography. A number of aryl and alkyl/aryl phosphate esters, polychlorinated paraffins and chemicals suggested as PCB-substitutes were chromatographed and the corresponding log P_oct-values calculated. Values for the phosphate esters corresponded reasonably well with previously reported data while data for other, often more complex compound mixtures (eg PCB-substitutes), need further evaluation. The use of the chromatographic system for screening purposes in work on environmentally significant data of possible organic pollutants is discussed.     

Responses to projected changes in climate and UV-B at the species level

Environmental manipulation experiments showed that species respond individualistically to each environmental-change variable. The greatest responses of plants were generally to nutrient, particularly nitrogen, addition. Summer warming experiments showed that woody plant responses were dominant and that mosses and lichens became less abundant. Responses to warming were controlled by moisture availability and snow cover. Many invertebrates increased population growth in response to summer warming, as long as desiccation was not induced. CO2 and UV-B enrichment experiments showed that plant and animal responses were small. However, some microorganisms and species of fungi were sensitive to increased UV-B and some intensive mutagenic actions could, perhaps, lead to unexpected epidemic outbreaks. Tundra soil heating, CO2 enrichment and amendment with mineral nutrients generally accelerated microbial activity. Algae are likely to dominate cyanobacteria in milder climates. Expected increases in winter freeze-thaw cycles leading to ice-crust formation are likely to severely reduce winter survival rate and disrupt the population dynamics of many terrestrial animals. A deeper snow cover is likely to restrict access to winter pastures by reindeer/caribou and their ability to flee from predators while any earlier onset of the snow-free period is likely to stimulate increased plant growth. Initial species responses to climate change might occur at the sub-species level: an Arctic plant or animal species with high genetic/racial diversity has proved an ability to adapt to different environmental conditions in the past and is likely to do so also in the future. Indigenous knowledge, air photographs, satellite images and monitoring show that changes in the distributions of some species are already occurring: Arctic vegetation is becoming more shrubby and more productive, there have been recent changes in the ranges of caribou, and "new" species of insects and birds previously associated with areas south of the treeline have been recorded. In contrast, almost all Arctic breeding bird species are declining and models predict further quite dramatic reductions of the populations of tundra birds due to warming. Species-climate response surface models predict potential future ranges of current Arctic species that are often markedly reduced and displaced northwards in response to warming. In contrast, invertebrates and microorganisms are very likely to quickly expand their ranges northwards into the Arctic.     

Co-management: concepts and methodological implications

Co-management, or the joint management of the commons, is often formulated in terms of some arrangement of power sharing between the State and a community of resource users. In reality, there often are multiple local interests and multiple government agencies at play, and co-management can hardly be understood as the interaction of a unitary State and a homogeneous community. An approach focusing on the legal aspects of co-management, and emphasizing the formal structure of arrangements (how governance is configured) runs the risk of neglecting the functional side of co-management. An alternative approach is to start from the assumption that co-management is a continuous problem-solving process, rather than a fixed state, involving extensive deliberation, negotiation and joint learning within problem-solving networks. This presumption implies that co-management research should preferably focus on how different management tasks are organized and distributed concentrating on the function, rather than the structure, of the system. Such an approach has the effect of highlighting that power sharing is the result, and not the starting point, of the process. This kind of research approach might employ the steps of (1) defining the social-ecological system under focus; (2) mapping the essential management tasks and problems to be solved; (3) clarifying the participants in the problem-solving processes; (4) analyzing linkages in the system, in particular across levels of organization and across geographical space; (5) evaluating capacity-building needs for enhancing the skills and capabilities of people and institutions at various levels; and (6) prescribing ways to improve policy making and problem-solving.     

Understanding heavy metal and suspended solids relationships in urban stormwater using simulated rainfall

Urban stormwater from simulated rainfall on three different landuses in Queensland State, Australia (residential, industrial, commercial) was analysed for heavy metals and physico-chemical parameters such as Dissolved Organic Carbon (DOC) and Total Suspended Solids (TSS). Rainfall events were simulated using a specially designed rainfall simulator for paved surfaces. Event mean concentration samples were separated into five different particle sizes and analysed individually for eight metal elements (Zn, Fe, Cr, Cd, Cu, Al, Mn and Pb). Multivariate data analysis was carried out for the data thus generated. It was found that DOC and TSS influence the distribution of the metals in the different particle size classes. Zn was correlated with DOC at all three sites. Similarly, Pb, Fe and Al were correlated with TSS at all sites. The distribution of Cu was found to vary between the three sites, whilst Cd concentrations were too low to assess any relationships with other parameters. No correlation between Electrical Conductivity (EC), pH and heavy metals was found at the three sites. The identification of physico-chemical parameters influencing the distribution process kinetics of heavy metals in urban stormwater will significantly enhance the efficiency of urban stormwater management systems.     

Solid waste treatment within the framework of life-cycle assessment

Traditionally, treatment of solid waste has been given limited attention in connection with life-cycle assessments (LCAs). Often, only the amounts of solid wastes have been noted. This is unsatisfactory since treatment of solid waste, e.g. by landfilling or incineration, is an operation, requiring inputs and producing outputs, which should be described in the inventory of an LCA, in parallel to other operations. However, there are difficulties in describing emissions from solid waste treatments and there is a need for development of such methods. In this paper an approach for describing emissions from incineration and landfilling is outlined. Methodological questions concerning the time-frame and allocation principles are discussed. Methods for estimating potential emissions from landfilling of municipal solid waste and industrial wastes are suggested. The methods are used for calculating potential emissions from landfilling of some typical wastes. These emissions are compared with the emissions from other stages in the life cycle for some materials and wastes. it is shown that the potential emissions from landfilling are, for some products, of importance for the final results. Hence, if emissions from landfilling are neglected, or underestimated, results and conclusions in an LCA may be misleading.     

北极4个亚区的影响分析

在评价北极陆地生态系统影响时,人们常常强调物种和生态系统对环境变化响应的地理变化,这种变化往往与气候、生物多样性、植被带、生态系统结构和功能的南-北梯度相关联,可是,环境、生态系统的功能和结构上,以及环境史和当前气候变化的明显东-西变化显然也很重要.尽管一些地方变得温暖,但另一些地方却降温了,海洋、群岛和山脉等地理屏障的东西差异过去也对物种和植被带响应气候变化而改变分布区的能力产生了很大影响,同时,这些地理屏障为种群遗传分化和生物多样性热点区的形成提供了必要的隔离条件,这些屏障在未来气候变暖时,也将影响物种重新分布的能力.为了说明这种东西向的变化,同时也避免过分笼统或过于专业化,基于大尺度的天气和气候形成因素,北极气候影响评价项目确定了4个主要亚区.通过模拟与4个北极气候影响评价亚区有关的主要信息,导致物种分布区发生改变的地理屏障,特别是大陆的分布和海洋产生的隔离,明显会影响植被带的向北移动.对植被区向北移动的地理限制或者促进将影响将来碳的贮存和释放,以及生物圈与大气之间水和能量的交换.此外,气候变化使受威胁物种数量在各个亚区之间差别很大(白令海地区别尤其是热点),各个植被亚区重新分布的能力差异将影响每个区的生物多样性.总而言之,亚区分析表明,在整个北极地区水平上概括生态系统结构和功能的反应、物种的丧失,以及生物圈对气候系统的反馈的趋势是困难的,说明需要对北极陆地生态系统对于气候变化响应的空间变化性有深刻的认识.